Ultraviolet (UV) light degradation of materials is a significant problem for many materials. Although there are various UV protective materials known in the art, a need exists for more improvements in such materials, and preferably for more effective UV light blocking UV materials, especially those that provide long term protection (i.e., at least 10 years) protection for articles intended to have a long useful life outdoors. In particular, materials (e.g., films) made with polymers containing aromatic compounds (e.g., aromatic polyesters, aromatic polycarbonates, polystyrenes, polyethylene 2,6 naphthalate, and certain polyimides (e.g., those available under the trade designations “ULTEM” from Sabic Innovative Plastics, Pittsfield, Mass., and “KAPTON” from E.I. DuPont de Nemours, Wilmington, Del.) need substantial UV protection to last more than 10 years outdoors.
2,6 polyethylenenaphthalate (PEN) has been used to make a variety of articles, including films and multilayer optical films (e.g., mirror films and reflective polarizer films). Mirror films have been used in daylighting applications for guiding sun light deep into the interior of buildings and as solar concentrating mirrors. Mirror films have also been used as reflectors in light emitting diode (LED) lighted displays, for example, to increase their efficiency. Reflective polarizer films have been used, for example, for brightness enhancement in projectors and liquid crystal displays including outdoor displays.